I've lost the reference to an old microwave book that explained the cavity resonance method. One method was to make a disk of the material of a certain thickness that was the same radius as a cylindrical microwave cavity. You measured the resonant frequency and cavity Q before the disk was inserted and after the disk was inserted into the bottom of the cavity. The change in f gave you the dielectric constant and the change in Q gave you your loss tangent. I can't remember the equations to relate delta fr and delta Q to Dk and tan delta. Does anyone else remember this technique? The cavity was cylindrical with a side launch from rectangular waveguide. -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Matthias Bergmann Sent: Wednesday, May 25, 2005 7:32 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Determination of relative permittivity Hello, quite a lot of discussions deal about the (effective) permittivity, but how do I determine it ? I would like to measure the complex permittivity of synthetic materials in a frequency range between 1 till 500 MHz. I know there are methods like Parallel plate, Reflection wave, S Parameters or Cavity to measure it, but, it's sort of weird, I didn't find any paper which explains how to construct a measurement system. So, are there any basic papers or books you can recommend me ? Best regards, Matthias Bergmann ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu